Transport Canada publishes advanced NPA for change to the type design of an aeronautical product

Transport Canada Civil Aviation has been working on a revision to CAR 521 since 2010 with several consultations, both internal and external. Due to many other governmental priorities, the authority has not been able to progress as quickly as it would like. In the last several months, it has been preparing an NPA based on all the feedback received.

An advanced NPA to revise CAR 521 was issued in July 2015, covering 10 issues that were identified during this period:

  1. Clarification of terminology and administrative text changes.
  2. Alternate method of data approval.
  3. Definition of threshold for a major design change to CAN-TSO articles.
  4. Issuance of special conditions-airworthiness for an auxiliary power unit.
  5. Clarification regarding requirements associated with reporting and investigation of service difficulty reporting.
  6. Clarification on part design approvals requirements.
  7. Addition of early ETOPS as an optional approval granted as part of a type certification for transport category aeroplanes.
  8. Expansion in applicability for a flight test operations manual.
  9. Addition of requirements for function and reliability test flights to normal category turbojets.
  10. Clarification regarding requirements associated with validation and acceptance of foreign approvals.

In total, there are 90 proposals for changes to the text of CAR 521. In most cases, there are changes to the wording to provide better clarification to the intent, such as changing conformity to compliance and the reintroduction of major and minor design change terminology. In all the revisions, there are three significant proposed changes that may affect the modification business.

One proposal is to revise 521.154, which covers minor design changes, to remove the applicability to design approval holders and to include wording that it indicates minor changes may be approved with procedures acceptable to the minister. The wording, as such, seems to indicate all minor changes regardless of who does them needs to be completed by this method. It may be in conflict with AWM 571.06, which states that minor changes can be completed by anyone using acceptable data. The intent of the acceptable data was to allow those in the field to make the determination on what was acceptable.

Additionally, the revision is meant to clear up the issue with respect to a delegate being able to approve a minor change. The intent is to make it clear that anyone who has acceptable procedures for minor changes can produce data that meets the definition of "acceptable data." However, the current proposed wording may have unintended consequences and further restrict a modification shop from carrying out minor modifications. This would further affect Canadian shops with respect to competing with U.S. shops. One of the overall goals of the TCCA has been to provide a vehicle that would even the playing field between Canadian and U.S. shops.

Currently, there are specific documents identified as acceptable to be used to identify an approved design. The proposal in this NPA is to allow for other forms to be used to approve major design changes. Currently, CAR 521 only identifies a type certificate, STC, RDA and TSO approval. This revision would allow delegates to create procedures and a document that would identify an approved major design change, thereby opening the door to "one-off approvals" as was done 20 years ago.

The final significant change is for the definition and requirements of a certification plan. The current wording is restrictive in the sense that it implies the applicant would have a complete product and definition of the product at the time of application, when in reality throughout the program several changes are made. The intent is to better define what a certification plan really is intended to do. It recognizes the fact that compliance is not yet demonstrated and all the details may not be known at the time of application. However, it is trying to implement requirements so that the applications are made at an advanced stage of the program.

The plan with this advanced NPA is to gather comments up to Sept. 26, 2015, and then carry out face-to-face meetings. Also, all comments made during the NPA process will be provided to the CARAC members for review. A final NPA will be drafted for acceptance by CARAC, although no proposed date has been set. 

Contact Ric Peri, AEA vice president of government and industry affairs, by email at or by phone at 202-589-1144.